The invention relates to a method for space-saving-variable length encoding. The input information items may represent characters, bytes, words, microprocessor instructions, etc. They may have uniform lengths or not. The principle of the encoding is that certain information items occur more frequently than others, so that mapping the former on relatively short code bit groups will diminish the overall amount of code bits. The technology for this mapping has been well known in the art. For progressive decoding, a particular code bit group is delimited in the stream of coded bits, decoded, and then the beginning of the next code bit group will be instantly visible. The decoding then becomes a straightforward job. In fact, the selecting of the various code bit groups has been designed in such way that the above delimiting is always easy; naturally, this is done for the most probable direction of the encoding, such as forward in the flow of time when encoding a more or less continuous signal such as speech. Regressive decoding, on the other hand, is less simple, because the delimiting of a single code bit group in this direction is often impossible through the particular selecting strategy. In principle, a trial and error regressive procedure may have a high probability for success, but any failure in delimiting a single code bit group will force the decoding to go back still further. In fact, both the larger decoding delay itself and the spread in the decoding delay are detrimental to the overall expediency of the decoding process.